PCV System: Maintenance: Notes

An engine may idle slow or rough due to clogged PCV valve or ventilation system. Never adjust fuel injection system without first checking valve and system. If PCV valve or system is clogged, all crankcase ventilation will stop and could result in serious engine damage.

It is recommended the crankcase ventilation system be checked more frequently if vehicle is operated under severe conditions (extreme dust, prolonged idling, trailer hauling or short trips in cold weather).